std::result_of

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Defined in header <type_traits>
template< class > class result_of; //not defined	(1)	(since C++11)
template< class F, class... ArgTypes > class result_of<F(ArgTypes...)>;	(2)	(since C++11)

Deduces the return type of a function call expression at compile type.

Member types

Member type	Definition
type	the return type of the function F if called with the arguments ArgTypes...

Possible implementation

template<class> class result_of;   template<class F, class... ArgTypes> struct result_of<F(ArgTypes...)> { typedef decltype( std::declval<F>()(std::declval<ArgTypes>()...) ) type; };

Example

struct S {
    double operator()(char, int&);
};
 
int main()
{
    std::result_of<S(char, int&)>::type f = 3.14; // f has type double
}

See also

declval (C++11)	obtains the type of expression in unevaluated context (function template)